Sharing more photos on AppleTV

Then you are mistaken. As I said, the 2nd gen works the same way as the 4k in that regard. When setting up the screensaver you pick a source and a select batch are cached. Then they are available on the system at any time, and are no longer connected to that source, and you would have to go to the settings to cache a new batch.

If it was actually using home sharing for the screensaver then your computer would need to be on and running iTunes each time you wanted to run the screensaver.

The 1st gen was the only one able to do it because it had an accessible hard drive and the photos resided on the system.

Again, if you want to see your full library you need to actually use home sharing (via the computers app) or put it into iCloud and use the Photos app. Using the slideshow isn't that different from using a screensaver in practice, apart from having to start it manually. You would still be able to set it to random and have it up while listening to music.

Not a problem.

Unfortunately, you will run into the same thing with iCloud. As I had said previously it is cached no matter what the source. So That is why I suggested uploading them to iCloud, which gives you access to them in the photos app, and then using the slideshow function. Again, it is not that different. You just need to start it manually but you can still have it set to random and it have it going while your music is playing.

Well I’m not sure what to tell you because I’ve had every version and the only one that allowed that was the 1st gen. Perhaps that was the model you had. If it really was a 2nd Gen and was showing different ones each time then you would have had to set it up to cache a new batch each time. It literally wouldn’t be possible to do it any other way.

The 1st gen was the only model that allowed content to be synced and stored. From the 2nd Gen onwards it has been streaming only, with a small portion temporarily cached for the screensaver.

You can use iCloud Photo Library to Store your full collection, up to 2TB and then use the slideshow function via the photos app on Apple TV. If you don’t want to store in the cloud you can use home sharing.

If you are using the photos for a screensaver it doesn’t matter what the source is, only a select group will be cached. The same was true for the 2nd Gen

You would need to go into the computers app and select your photo library to view manually, and then start a slideshow. You computer would need to be on and running iTunes each time you want to view your photos.

If you want to bypass home sharing you would need to enable iCloud Photo Library and store your collection there. Then you can access on the photos app, and start the slideshow from there